CA1207356A - Device for robot manipulator - Google Patents
Device for robot manipulatorInfo
- Publication number
- CA1207356A CA1207356A CA000410423A CA410423A CA1207356A CA 1207356 A CA1207356 A CA 1207356A CA 000410423 A CA000410423 A CA 000410423A CA 410423 A CA410423 A CA 410423A CA 1207356 A CA1207356 A CA 1207356A
- Authority
- CA
- Canada
- Prior art keywords
- servo
- wire guide
- manipulator arm
- wire
- base
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/10—Programme-controlled manipulators characterised by positioning means for manipulator elements
- B25J9/104—Programme-controlled manipulators characterised by positioning means for manipulator elements with cables, chains or ribbons
- B25J9/1045—Programme-controlled manipulators characterised by positioning means for manipulator elements with cables, chains or ribbons comprising tensioning means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J17/00—Joints
- B25J17/02—Wrist joints
- B25J17/0258—Two-dimensional joints
- B25J17/0266—Two-dimensional joints comprising more than two actuating or connecting rods
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/02—Programme-controlled manipulators characterised by movement of the arms, e.g. cartesian coordinate type
- B25J9/04—Programme-controlled manipulators characterised by movement of the arms, e.g. cartesian coordinate type by rotating at least one arm, excluding the head movement itself, e.g. cylindrical coordinate type or polar coordinate type
- B25J9/046—Revolute coordinate type
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/10—Programme-controlled manipulators characterised by positioning means for manipulator elements
- B25J9/14—Programme-controlled manipulators characterised by positioning means for manipulator elements fluid
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/20—Control lever and linkage systems
- Y10T74/20207—Multiple controlling elements for single controlled element
Abstract
ABSTRACT
A robot manipulator having a multiply articulated manipulator arm rotatably mounted on a swivelling base, wherein all the servo-cylinders are placed in the base and wherein a mechanical power transmission mechanism is disposed between the tool holder and each of the parts of the manipulator arm respectively and the associated servo-cylinder. The linear move-ment of the individual servo-cylinders is converted into a substantially proportional rotary movement over the whole working range of the servo-cylinder. The power transmission mechanisms are so designed that when one or more of them is in action and the portions of the manipulator arm are moved in relation to one another, the other power transmission mechanisms are not influenced as a result of these movements. All the servo-cylinders have a piston rod, the diameter of which is reduced to below the bending limit for a conventional freely mounted piston rod, since the piston rod is rigidly connected, at one end, to the piston of the servo cylinder and is rigidly connected, at the other end, to a member adapted to slide or roll in fixed guides, as a result of which the contact area and hence the friction between the piston rod and piston-rod packing is reduced to a minimum.
A robot manipulator having a multiply articulated manipulator arm rotatably mounted on a swivelling base, wherein all the servo-cylinders are placed in the base and wherein a mechanical power transmission mechanism is disposed between the tool holder and each of the parts of the manipulator arm respectively and the associated servo-cylinder. The linear move-ment of the individual servo-cylinders is converted into a substantially proportional rotary movement over the whole working range of the servo-cylinder. The power transmission mechanisms are so designed that when one or more of them is in action and the portions of the manipulator arm are moved in relation to one another, the other power transmission mechanisms are not influenced as a result of these movements. All the servo-cylinders have a piston rod, the diameter of which is reduced to below the bending limit for a conventional freely mounted piston rod, since the piston rod is rigidly connected, at one end, to the piston of the servo cylinder and is rigidly connected, at the other end, to a member adapted to slide or roll in fixed guides, as a result of which the contact area and hence the friction between the piston rod and piston-rod packing is reduced to a minimum.
Description
~2~7~S6 .
The present invention relates to a robot manipulator of the kind which has a multiply articulated manipulator arm rotatably mounted in a swivelling base, and wherein a front portion of the manipulator arm is rotatably connected, via a three-point connection, to an intermediate portion of the manipulator arm so that the front portion of the manipulatox arm can be turned, up to a certain angle, in all possible directions in relation to the rear portion of the manipulator arm by means of two longitudinally displaceable, substantially parallel rods, one end of which is rotatably secured to the front portion oE the manipulator arm to form t~o of the points in said three-point connection, the third point consisting of a universal joint, and wherein the manipulator arm with a tool holder is controlled by a system with hydraulic servo-cylinders. Such robot manipulators have their movement pattern programmed by a person taking hold of the manipulator arm and guiding it in the required movement patternr which the robot manipulator can then repeat automatically.
One great disadvantage of the known robot manipulators of this kind is that it is difficult for a person to move the manipulator arm by hand with the required precision during the programming. T~is is due partly to the fact that the manipulator arm is comparatively heavy, because hydraulic servo-cylinders for movements of the manipulator arm are mounted in its various arm portions, and it is due partly to comparatively great friction between the piston rods and the piston-rod packing in the hydraulic servo-cylinders of the robot manipulator.
An attempt has previously been made to remedy the above-~73~
mentioned disadvantage by a separate passive programming arm with little mass and friction. Since the movements of the programming arm are stored on a so-called disc or corresponding magnetic storage medium, the robot manipulator can execute the same move-ments when it is controlled by the same disc.
A disadvantage of the separate programming arm, however, is the increased cost of the robot manipulator which the separate programming arm involves. ~nother disadvantage of the separate programming arm is that it necessarily requires like placing of the tool on the manipulator arm and the programming arm and this has proved to involve difficulties in practice.
Another disadvantage of the known robot manipulators of this kind is that khe decomposition of the position measuring system in the various servo systems which control the rotary move-ments of the robot manipulator cannot be transmitted proportionally to the working range of the manipulator arm because the linear movements of the hydraulic servo-cylinders have to be converted into rotary movements, which leads to a less precise repetition of the programmed movement pattern.
Yet another disadvantage of the known robot manipulators of this kind is that the connections bet~een the front portion of the manipulator arm and the piston rods of the hydraulic servo-cylinders which move the front portion in relation to tha rear portion of the manipulator arm, are ball-and-socket joint connections which are expensive and difficult to make sufficiently accurate for this purpose, while at the same time the movement amplitudes in a ball-and-socket joint are limited.
Another disadvantage of the known robot manipulators of this kind is a less effective means to prevent the above-mentioned piston rods from twisting in relation to one another during displacement.
A disadvantage which follows from the fact that hydraulic servo-cylinders are placed in the manipulator arm in the known robot manipulators of this kind is that drops of oil from the hydraulic system can be most undesirable in individual cases, for example when handling edible material.
The object of the invention is to provide a robot manipulator of the above-mentioned kind without a separate programming arm and wherein the other above-mentioned disadvantages are eliminated, so that a person can easily move the manipulator arm by hand with the required precision during programming of the movement pattern of the robot manipulator.
According to the invention there is provided a device for robot manipulators of the kind which have a multiple articulated manipulator arm rotatably mounted in a swivelling base and wherein a front portion of the manipulator arm is rotatably connected, via a three-point connection, to a portion of the manipulator arm situated behind so that the front portion of the manipulator arm can be turned, up to a certain angle, in all possible directions in relation to the portion of the manipulator arm situated behind, by means of two longitudinally displaceable, substantially parallel control rods, one end of each of said rods being pivotally secured to the front portlon A
l~07as6 of the manipulator arm and forming two of the points in said three-point connection, the third point consisting of a universal joint connection and wherein the manipulator arm with a tool holder is controlled by a system with hydraulic sexvo-cylinders, characterized in that all the servo-cylinders are placed in the base of the robot manipulator and that mechanical power trans-mission means~are disposed between the tool holder or each of the parts of.thë manipulator arm respectively and the associated servo-cylinder, and that the front portion of the manipulator arm is formed with a bearing housing set transversely and in which a journal is mounted for rotation but not for displacement, and each of the parallel rods is respectively mounted on each end of the journal for pivoting, and a transverse member is pivotally connected to each of the parallel rods near the connection points of the rods to the journal, and the transverse member has a groove in the longitudinal direction of the rods, and a pin is rigidly connected to the intermediate portion of the manipulator arm and is received for sliding in the groove, wherein an extension of the center line of the pin passes through the center line of a spindle mounted in the intermediate portion, and said spindle is connected to the universal joint.
By way of illustration, but not limitation, one embodiment of the invention is shown in the drawings, in which:
Figure 1 shows diagrammatically, a perspective basic drawing of a robot manipulator with a device according to the invention;
_ ,. ~ " ~ ;~6 Figure 2 shows, diagrammatically and from the side, the mechanical arrangement for transmitting movements from a hydraulic servo-cylinder mounted fixedly in the base of the robot manipulator to a longitudinally displaceable stay in the manipulator arm of the robot manipulator, which stay participates in controlling movements of the manipulator arm in its front arm portion;
Figure 3 shows, partially in section and from the side, the front portion of the manipulator arm with a device according to the invention;
Figure 4 shows, from above, the same part of the manipulator arm as is shown in Figure 3;
Figure 5 shows diagrammatically and partially in section, any one of the hydraulic servo cylinders of the robot manipulator with the associated arrangement up to the rotatable shaft which is acted upon by the servo-cylinder; and Figure 6 is a graphic representation of the transmission -4a-~73~
of movement from the hydraulic servo-cylinder to the rotatable shaft which is shown in Figure 5.
In Figure 1 of the drawing, the reference numeral 1 designates the base of the robot manipulator which is rotatably mounted on a footplate 2 and can be turned by means of a first hydraulic servo-cylinder 3 placed in the base 1, in that the servo-cylinder 3 acts, via a first link 4, on a first crank arm 5 secured to a fi~ed shaft 6 of the base 1. One end of the back portion 7 of the manipulator arm is rotatably mounted on the base 1, while the other end of the back portion 7 of the manipulator arm is rotatably connected to one end of an intermediate portion 8, the other end of which is connected via a universal joint 9 (see Figure 3) to a ront portion 10 of the manipulator arm. The front portion 10 of the manipulator arm 7, 8, 10, is eqwipped with a rotatable tool holder 11.
The back portion 7 of the manipulator arm 7, 8, 10 can ; be rotated in relation to the base 1 by means o a second hydraulic : servo-cylinder 12 placed in the base 1, in that the ~ervo-cylinder 12 acts, via a second link 13, on a second crank arm 14 secured to the pivot shaf~ 15 of the back portion 7.
The intermediate portion 8 of the manipulator arm 7-, 8, 10 can be rotated in relation to the. back portion 7 by means of a third hydraulic servo-cylinder 16 placed in the base 1, in that the servo-cylinder 16 acts, via a third link 17 on a third crank arm 18 through a projection 19 secured to this, while the third crank arm 18 is rotatably connected to one end of a stay 20, the other end of which is pivotally connected to the inte.rmediate portion 8 of manipulator arm 7, 8, 10.
~ ~2~73~;6 By means of three like power transmission mechanisms from three hydraulic servo-cylinders placed in the base 1, the front portion 10 of the manipulator arm 7, 8, 10 can be turned, up to a certain angle, in all possible directions in relation to the intermediate portion 8, and the tool holder 11 can rotate about its longitudinal axis.
For the sake of clarity, only one of the three above-mentioned like power transmitting mechanisms with the associated hydraulic servo-cylinder is shown in the drawing. The last-mentioned hydraulic servo-cylinder is designated by the reference numeral 21 and hereinafter is called the fourth hydraulic servo-cylinder.
Movements o the front portion 10 are caused by two longitudinally displaceable control rods placed in the intermediate portion 8 of the manipulator arm 7, 8, 10, only one of which, with the reference numeral 22, is shown :in Figure 1 for the sake of clarity. The other of said two control rods is shown in Figures 3 and 4 and desiynated by the reference numeral 23.
The rotation of the tool holder 11 about its longitudinal axis is brought about by means of action on a longitudinally displaceable control rod by a device which acts on the same known principle as a pump impeller. The last-mentioned control rod, which is shown ln Figures 3 and 4 and is designated by the refer-ence numeral 24, is also placed in the intermediate portion 8 of the manipulator arm 7, 8, 10, but is not shown in Figure 1 for the sake of clarity.
The longitudinally displaceable control rod 22 can be , . j, - 9 207;~6 displaced by means of the fourth hydraulic servo-cylinder 21 and a power transmission mechanism which is described in its broad features below.
The piston rod of the servo-cylinder 21 is pivotally connected via a guide which will be discussed in more detail below - to one end of a fourth link 25, the other end of which is pivotally connected to a projection 26 on a wire attachment pulley 27 which is pivotally mounted in the base l and which also acts as a crank arm. Secured to the wire attachment pulley 27 is a first wire 28 which is taken round the front of the wire attachment pulley 27 and which, via the back of a first rotatable wire guide pulley 29 mounted in the base 1 and via a second rotatable wire guide pulley 30 mounted on the back portion 7 of the manipulator arm 7, 8, 10 and under the pivotable connection of this to the intermediate portion 8, is taken back and secured to the back end of a rail 31. ~y its front end, this rail is pivotally mounted on a rocker arm 32 which is pivotally mounted on the intermediate portion 8 of the manipulator arm 7, 8, lOo The back end of the longitudinally displaceable control rod 22 is also pivotally ~0 mounted on the rocker arm 32.
Secured to the wire attachment pulley 27 are a second and a third wire 33 and 34 which are taken round the back of the wire attachment pulley 27, that is to say at the opposite side to the wire 28, and which, via the front of a third rotatable wire guide : pulley 35 mounted in the base 1 and via a second wire guide pulley 30 are taken ~orwards and secured to the front end of the rail 31.
Thus the two wires. 33 and 3~ have a parallel course over the whole t~
- ~o~
path. The first wire 28 has a course over the whole path which lies in a plane perpendicular to the axes of rotation of the wire attachment pulley 27 and the wire guide pulleys 29, 30 35 and between the wires 33 and 34 extending parallel. As a result of the fact that the first wire 28 crosses between the second and third wires 33 and 34 at the top of the second wire guide pulley 3n, the wire tension on the rail 31 is not oblique. The rail 31 is also provided with turnbuckles t not shown in the drawing, for the wires 28, 33 and 34O
The power transmission mechanism described above from the fourth hydraulic servo-cylinder 21 in the base 1 to the longitudinally displaceable control rod 22 in the intermediate portion 8 of the manipulator arm 7, 8, 10 is designed in such a manner that the back portion 7 o the manipulator arm 7, 8, 10 can be turned in relation to the base 1 and the intermediate portion 8 can be turned in relation to the back portion 7 without the wires 28, 33 and 34 being acted upon so that the control rod 22 in the intermediate portion 8 is displaced longitudinally. According to the invention, this is achieved in that the first and third wire guide pulleys 29, 35 are mounted in the base 1 at the same or substantially the same distance from the mounting of the associated wire securing pulley 27 in the ~ase 1, and in that the back portion 7 is mounted in the base 1 so that the axis of rotation of the back portion 7 preferably lies near to the common centre line of the first and third wire guide pulleys, 29, 35, for example 1/36th of the diameter of the wire guide pulleys 29, 35 ~elow, and so that the axis of rotation of the back portion 7 lies equally far away : - 8 from the axes of rotation of the first and third wire guide pulleys 29, 35, while at the same time the diameter of the first and third wire guide pulleys 29, 35 is selected so that so much wire 28 or 33, 34 respectively is wound on the wire guide pulleys 29, 35 respectively where the centre spacing between the wire guide pulleys 29, 35 respectively and the second wire guide pulley 30 is shortened as a result of the movement of the back portion 7, that the wire tension is kept constant, and that so much wire 33, 34 or 28 respectively is unwound from the wire guide pulley 35 or 29 respectively where the centre spacing between the wire guide pulleys 29, 35 respectively and the second wire guide pulley 30 is lengthened as a result o movement of the back portion 7, that the wire tension is kept constant, which altogether means that the second wire guide pulley 30 is not rotated and that the rail 31 is not displaced longitudinally as a result of movements of the back portion 7 in relation to the base 1. The second wire guide : pulley 30 is further mounted in the ~ack portion 7 at a distance from the axis of rotation between the back portion 7 and the intPrmediate portion 8 which is equal to or substantially equal to the radius of the second wire guide pulley 30, and on a point on the straight line connecting said axis of rotation and the axis of ~ .rotation of the back portion 7 in the base 1, while at the same ; time the diameter of the second wire guide pulley 30 is selected so and the axis of rotation of the rocker arm 32 is placed so in relation to the axis of rotation between the back portion 7 and the intermediate portion 8, that, on a movement OI the intermediate portion 8 in relation to the back portion 7, so much wire 28, 33, _ g _ .~J
34 is wound and unwound respectivel~ in relation to the second wire guide pulley 30 that the ~ire tension is kept constant when the spacing between the axis of rotation of the second wire guide pulley 30 and the connection point between the rocker arm 32 and the rail 31 is altered as a result of movement of the intermediate portion 8 in relation to the back portion 7, which means that the rail 31 is not displaced longitudinally as a result of movements of the intermediate portion 8 in relation to the bac~ portion 7.
It has proved advisable for the diameter of the first and third wire guide pul~eys 2~, 35 to be 4/5ths of the diameter of the second wire guide pulley 30 and for the distance between the axis of rotation of the back portion 7 in the base 1 and the axis of rotation of the second wire guide pulley 30 to be at least five times the diameter of the second wire guide pulley 30. The wire attachment pulley 27 must be so large that the wires 28 r 33 and 34 respectively never lose contact ~ith the ~irst and third wire guide pulleys 29 and 35 respectively when the back portion 7 of the manipulator arm 7, 8, 10 is moved in relation to the base 1 within a desired range of movement.
2Q It wi11 now ba explained in more detail, with reference to Figures 3 and 4 of the drawings, how the front portion lQ of the manipulator arm 7, 8, 10 of the robot manipulator and its tool holder 11 are connected to and moved by the three longitudinally displaceable control rods 22, 23 and 24 mounted in the inter-mediate portion 8 of the manipulator arm 7, 8, 10.
The front portion 10 of the manipulator arm 7, 8, lQ
is adapted to be able to be turned in relation to the intermediate ~s~
portion 8 about the axes A-A and B-B in Figures 3 and 4 of the drawings by means of its universal-joint connection 9 to the intermediate portion 8 situated behind via a spindle 36 which is rotatably mounted in the intermediate portion 8 and the front portion of which is formed as a part of the universal joint 9.
The tool holder 11 is connected to the rotatable spindle 36 via the universal joint 3. Screwed to the free end of the spindle 36 is a screw 37~ the free end o~ which is received in a so-called ball nut 38 (not self-locking) secured to the free end of the longitudinally displaceable control rod 24. When the control rod 24 and hence the ball nut 38 is displaced longitudinally by -the associated hydraulic servo~cylinder in the base 1 being activated, the scre~ 37 will be turned on th~ same principle as the spindle in a pump inpeller, whereupon the tool holder 11 is turned correspondingly.
The front portion 10 of the manipulator arm 7, 8, 10 is formed with a transverse bearing ho~lsing 39 in which a journal 40 is rotatably mounted. The journal 40 cannot be displaced longitudinally in the bearing housing 39. The free ends of the longitudinally displaceable control rods 22 and 23 are pivotally mounted, each at its own end of the journal 40.
The two pivotable connections between the journal 40 and the guide rods 22 and 23 constitute two of three points in a three-point connection between the front portion 10 of.the manipulator arm 7, 8, 10 and the intermediate portion 8. The third point of the three-point connection consists of the universal joint 9.
~SB
When the front portion 10 of the manipulator arm 7, 8, 10 is to be turned in relation to the intermediate portion 8 of the manipulator arm 7, 8, 10, about the axis B-B, the control rods 22 and 23 are displaced equally. When the front portion 10 of the manipulator arm 7, 8, 10 is to be turned in relation to the intermediate portion 8 of the manipulator arm 7, 8, 10, situated ~ehind, about the axis A-A, the control rods 22 and 23 are displaced in relation to one another. It will easily be understood that the front portion 10 o the manipulator arm 7, 8 10 can be adjusted, up to a certain angle, in all possibl~ directions in relation to the intermediate portion 8 of the manipulator arm 7, 8, 10, b~ diferent displacement o the control rods 22 and 23.
In order to prevent the control rods 22 and 23 from twisting in relation to one another during the displacement of the control rods 22 and 23, there is disposed in the vicinity of ; the connections o the contxol rods 22 and 23 to the journal 40 a transverse member 41, one end of ~hich is pivotally connected to the control rod 22 and the other end of which is pivotally connected to the control rod 23. The transverse member 41 is 20 formed in the middle with a groove 42 in the longitudinal direction of the control rods 22, 23. Received for sliding in the groove 42 is the free end of a pin 43 which is rigidly connected to the intermediate portion 8 of the manipulator arm 7, 8l lO in such a manner that an extension of the centre line 44 of the pin 43 passes through the centre line 45 of the spindle 36.
It is clear from the above that in connection ~ith the invention all the hydraulic servo-cylinders of the ro~ot manipulator are placed in the base l of the robot manipulator and that linear movements from all the hydraulic servo-cylinders are converted into rotary movements by means of a crank device. In order that the servo-systems of the robot manipulator may be satisfactory, it is important that their position measuring systems should be closely connected to the hydraulic servo-cylinders, and that the servo~mechanisms should have substantially the same dissolution in the position measuring system over the whole range of movement of the tool holder 11. According to the invention, this is achieved in that all the servo-systems of the robot manipulator have an arrangement which is explained below with reference to Figures 5 and 6. In Figure 5, the reference numeral 46 designates any one of the hydraulic servo~cylinders of the robot manipulator. The servo-cylinder 46 is rigidly mounted in the base 1 of the robot manipulator, which base is not shown in Figure 5. The piston rod 47 of the servo-cylinder 46 is rigidly connected to the piston 48 o the servo-cylinder 46, which piston is formed with seali~g grooves 49 (pressure-distribution grooves).
At the other end, the piston rod 47 of the servo-cylinder 46 is rigidly connected to a member 50 adapted to slide with rolling friction 51 in fixed guides.52. Pivotally mounted on the member 5Q is one end of a link 53, the other end of which is pivotally mounted on the end of a crank arm 54 rigidly connected to a rotatable shaft 55 mounted in the base 1 of the robot manipulator.
The measuring system of the servo~cylinder 46, which is not shown in the drawing, is connected by means of a steel wire 56 to a projection 57 on the member 50.
.
r~
As a result of the fact that the length a of the crank arm 54 and the length b of the link 53 and the distance c between the axis of rotation of the shaft 55 and the centre line of the piston rod 47 are in the ratio of a to 1.80a to 1.33a in relation to one another and that the distance d between the pivotal axis of the link 53 on the member 50 when this is in the outer position, and the point of intersection between the cen-tre line of the piston rod 47 and a centre line perpendicular to this through the axis of rotation of the shaft 55 is 0.39a, and that the stroke length _ of the servo-cylinder 46 is~s6~, the effect is achieved that the linear piston movement of the servo-cylinder is converted into rotar~ movement of the shaEt 55 so that the relationship between the angular rotation of the shaft 55 and the corresponding changes in position of the piston 48 of the servo-cylinder 46 is substantia~ly constan~ over the whole working range of the servo-cylinder 46.
The substantially linear ~ransmission of movement described above from the servo-cyli~lder 46 to the rotatable shaft 55 is shown graphically in Figure 6 where the curve in the 2Q coordinate system shown indicates the angle V as a function of the distance of the member 50 from the normal down from the centre line of the shaft 55 when the stroke length _ of the servo-cylinder 46 is set at 200 millimetres. The two actual dimensions _ and _ are marked out in the ahscissae.
According to the invention, the friction between the pi~ton rod 47 and the piston-rod packing 59 in all the hydraulic servo-cylinders 46 of the robot manipulator is reduced to a , ~L2~7;}56 minimum by a special arrangement ~hereby the diameter of the piston rod 47 is reduced to below the bending limit for a piston rod freely mounted in conventional manner. The arranyement is shown in Figure 5 and will be explained in more detail below. It was explained above that the piston rod 47 is rigidly connected to the piston 48 of the servo-cylinder 46 and that, at the other end, the piston rod 47 is rigidly connected to a member 50 adapted to slide with rolling friction 51 in fixed guides 52. At the piston rod side, the servo-cylinder 46 is equipped with an end member 58 in which, in addition to a piston-rod packing 59t there is mounted a roller bush 60 through which the piston rod 47 is taken. The roller bush 60 is so long that the portion of the piston rod 47 which is inside the roller bush 60 at any time acts as if it were fixed. As a result of the fact that the piston rod 47 according to the invention is fixed at both ends, it has been possible to reduce the diameter of the piston rod very considerably in relation to the diameter o~ piston rod which, in view of the bend-ing circumstances, would have been necessary if the piston rod 47 had been freely mounted at both ends in the usual manner. In this manner, it has been possible for example, to reduce a piston rod diameter ~rom ~0 millimetres to 8 millimetres. This means that the circumference of the piston rod is reduced from 62.8 milli-metres to 25.1 millimetres. Since the friction between the piston rod and the packing is proportional to the pressure of the packing per unit area, the friction is reduced correspondingly.
The present invention relates to a robot manipulator of the kind which has a multiply articulated manipulator arm rotatably mounted in a swivelling base, and wherein a front portion of the manipulator arm is rotatably connected, via a three-point connection, to an intermediate portion of the manipulator arm so that the front portion of the manipulatox arm can be turned, up to a certain angle, in all possible directions in relation to the rear portion of the manipulator arm by means of two longitudinally displaceable, substantially parallel rods, one end of which is rotatably secured to the front portion oE the manipulator arm to form t~o of the points in said three-point connection, the third point consisting of a universal joint, and wherein the manipulator arm with a tool holder is controlled by a system with hydraulic servo-cylinders. Such robot manipulators have their movement pattern programmed by a person taking hold of the manipulator arm and guiding it in the required movement patternr which the robot manipulator can then repeat automatically.
One great disadvantage of the known robot manipulators of this kind is that it is difficult for a person to move the manipulator arm by hand with the required precision during the programming. T~is is due partly to the fact that the manipulator arm is comparatively heavy, because hydraulic servo-cylinders for movements of the manipulator arm are mounted in its various arm portions, and it is due partly to comparatively great friction between the piston rods and the piston-rod packing in the hydraulic servo-cylinders of the robot manipulator.
An attempt has previously been made to remedy the above-~73~
mentioned disadvantage by a separate passive programming arm with little mass and friction. Since the movements of the programming arm are stored on a so-called disc or corresponding magnetic storage medium, the robot manipulator can execute the same move-ments when it is controlled by the same disc.
A disadvantage of the separate programming arm, however, is the increased cost of the robot manipulator which the separate programming arm involves. ~nother disadvantage of the separate programming arm is that it necessarily requires like placing of the tool on the manipulator arm and the programming arm and this has proved to involve difficulties in practice.
Another disadvantage of the known robot manipulators of this kind is that khe decomposition of the position measuring system in the various servo systems which control the rotary move-ments of the robot manipulator cannot be transmitted proportionally to the working range of the manipulator arm because the linear movements of the hydraulic servo-cylinders have to be converted into rotary movements, which leads to a less precise repetition of the programmed movement pattern.
Yet another disadvantage of the known robot manipulators of this kind is that the connections bet~een the front portion of the manipulator arm and the piston rods of the hydraulic servo-cylinders which move the front portion in relation to tha rear portion of the manipulator arm, are ball-and-socket joint connections which are expensive and difficult to make sufficiently accurate for this purpose, while at the same time the movement amplitudes in a ball-and-socket joint are limited.
Another disadvantage of the known robot manipulators of this kind is a less effective means to prevent the above-mentioned piston rods from twisting in relation to one another during displacement.
A disadvantage which follows from the fact that hydraulic servo-cylinders are placed in the manipulator arm in the known robot manipulators of this kind is that drops of oil from the hydraulic system can be most undesirable in individual cases, for example when handling edible material.
The object of the invention is to provide a robot manipulator of the above-mentioned kind without a separate programming arm and wherein the other above-mentioned disadvantages are eliminated, so that a person can easily move the manipulator arm by hand with the required precision during programming of the movement pattern of the robot manipulator.
According to the invention there is provided a device for robot manipulators of the kind which have a multiple articulated manipulator arm rotatably mounted in a swivelling base and wherein a front portion of the manipulator arm is rotatably connected, via a three-point connection, to a portion of the manipulator arm situated behind so that the front portion of the manipulator arm can be turned, up to a certain angle, in all possible directions in relation to the portion of the manipulator arm situated behind, by means of two longitudinally displaceable, substantially parallel control rods, one end of each of said rods being pivotally secured to the front portlon A
l~07as6 of the manipulator arm and forming two of the points in said three-point connection, the third point consisting of a universal joint connection and wherein the manipulator arm with a tool holder is controlled by a system with hydraulic sexvo-cylinders, characterized in that all the servo-cylinders are placed in the base of the robot manipulator and that mechanical power trans-mission means~are disposed between the tool holder or each of the parts of.thë manipulator arm respectively and the associated servo-cylinder, and that the front portion of the manipulator arm is formed with a bearing housing set transversely and in which a journal is mounted for rotation but not for displacement, and each of the parallel rods is respectively mounted on each end of the journal for pivoting, and a transverse member is pivotally connected to each of the parallel rods near the connection points of the rods to the journal, and the transverse member has a groove in the longitudinal direction of the rods, and a pin is rigidly connected to the intermediate portion of the manipulator arm and is received for sliding in the groove, wherein an extension of the center line of the pin passes through the center line of a spindle mounted in the intermediate portion, and said spindle is connected to the universal joint.
By way of illustration, but not limitation, one embodiment of the invention is shown in the drawings, in which:
Figure 1 shows diagrammatically, a perspective basic drawing of a robot manipulator with a device according to the invention;
_ ,. ~ " ~ ;~6 Figure 2 shows, diagrammatically and from the side, the mechanical arrangement for transmitting movements from a hydraulic servo-cylinder mounted fixedly in the base of the robot manipulator to a longitudinally displaceable stay in the manipulator arm of the robot manipulator, which stay participates in controlling movements of the manipulator arm in its front arm portion;
Figure 3 shows, partially in section and from the side, the front portion of the manipulator arm with a device according to the invention;
Figure 4 shows, from above, the same part of the manipulator arm as is shown in Figure 3;
Figure 5 shows diagrammatically and partially in section, any one of the hydraulic servo cylinders of the robot manipulator with the associated arrangement up to the rotatable shaft which is acted upon by the servo-cylinder; and Figure 6 is a graphic representation of the transmission -4a-~73~
of movement from the hydraulic servo-cylinder to the rotatable shaft which is shown in Figure 5.
In Figure 1 of the drawing, the reference numeral 1 designates the base of the robot manipulator which is rotatably mounted on a footplate 2 and can be turned by means of a first hydraulic servo-cylinder 3 placed in the base 1, in that the servo-cylinder 3 acts, via a first link 4, on a first crank arm 5 secured to a fi~ed shaft 6 of the base 1. One end of the back portion 7 of the manipulator arm is rotatably mounted on the base 1, while the other end of the back portion 7 of the manipulator arm is rotatably connected to one end of an intermediate portion 8, the other end of which is connected via a universal joint 9 (see Figure 3) to a ront portion 10 of the manipulator arm. The front portion 10 of the manipulator arm 7, 8, 10, is eqwipped with a rotatable tool holder 11.
The back portion 7 of the manipulator arm 7, 8, 10 can ; be rotated in relation to the base 1 by means o a second hydraulic : servo-cylinder 12 placed in the base 1, in that the ~ervo-cylinder 12 acts, via a second link 13, on a second crank arm 14 secured to the pivot shaf~ 15 of the back portion 7.
The intermediate portion 8 of the manipulator arm 7-, 8, 10 can be rotated in relation to the. back portion 7 by means of a third hydraulic servo-cylinder 16 placed in the base 1, in that the servo-cylinder 16 acts, via a third link 17 on a third crank arm 18 through a projection 19 secured to this, while the third crank arm 18 is rotatably connected to one end of a stay 20, the other end of which is pivotally connected to the inte.rmediate portion 8 of manipulator arm 7, 8, 10.
~ ~2~73~;6 By means of three like power transmission mechanisms from three hydraulic servo-cylinders placed in the base 1, the front portion 10 of the manipulator arm 7, 8, 10 can be turned, up to a certain angle, in all possible directions in relation to the intermediate portion 8, and the tool holder 11 can rotate about its longitudinal axis.
For the sake of clarity, only one of the three above-mentioned like power transmitting mechanisms with the associated hydraulic servo-cylinder is shown in the drawing. The last-mentioned hydraulic servo-cylinder is designated by the reference numeral 21 and hereinafter is called the fourth hydraulic servo-cylinder.
Movements o the front portion 10 are caused by two longitudinally displaceable control rods placed in the intermediate portion 8 of the manipulator arm 7, 8, 10, only one of which, with the reference numeral 22, is shown :in Figure 1 for the sake of clarity. The other of said two control rods is shown in Figures 3 and 4 and desiynated by the reference numeral 23.
The rotation of the tool holder 11 about its longitudinal axis is brought about by means of action on a longitudinally displaceable control rod by a device which acts on the same known principle as a pump impeller. The last-mentioned control rod, which is shown ln Figures 3 and 4 and is designated by the refer-ence numeral 24, is also placed in the intermediate portion 8 of the manipulator arm 7, 8, 10, but is not shown in Figure 1 for the sake of clarity.
The longitudinally displaceable control rod 22 can be , . j, - 9 207;~6 displaced by means of the fourth hydraulic servo-cylinder 21 and a power transmission mechanism which is described in its broad features below.
The piston rod of the servo-cylinder 21 is pivotally connected via a guide which will be discussed in more detail below - to one end of a fourth link 25, the other end of which is pivotally connected to a projection 26 on a wire attachment pulley 27 which is pivotally mounted in the base l and which also acts as a crank arm. Secured to the wire attachment pulley 27 is a first wire 28 which is taken round the front of the wire attachment pulley 27 and which, via the back of a first rotatable wire guide pulley 29 mounted in the base 1 and via a second rotatable wire guide pulley 30 mounted on the back portion 7 of the manipulator arm 7, 8, 10 and under the pivotable connection of this to the intermediate portion 8, is taken back and secured to the back end of a rail 31. ~y its front end, this rail is pivotally mounted on a rocker arm 32 which is pivotally mounted on the intermediate portion 8 of the manipulator arm 7, 8, lOo The back end of the longitudinally displaceable control rod 22 is also pivotally ~0 mounted on the rocker arm 32.
Secured to the wire attachment pulley 27 are a second and a third wire 33 and 34 which are taken round the back of the wire attachment pulley 27, that is to say at the opposite side to the wire 28, and which, via the front of a third rotatable wire guide : pulley 35 mounted in the base 1 and via a second wire guide pulley 30 are taken ~orwards and secured to the front end of the rail 31.
Thus the two wires. 33 and 3~ have a parallel course over the whole t~
- ~o~
path. The first wire 28 has a course over the whole path which lies in a plane perpendicular to the axes of rotation of the wire attachment pulley 27 and the wire guide pulleys 29, 30 35 and between the wires 33 and 34 extending parallel. As a result of the fact that the first wire 28 crosses between the second and third wires 33 and 34 at the top of the second wire guide pulley 3n, the wire tension on the rail 31 is not oblique. The rail 31 is also provided with turnbuckles t not shown in the drawing, for the wires 28, 33 and 34O
The power transmission mechanism described above from the fourth hydraulic servo-cylinder 21 in the base 1 to the longitudinally displaceable control rod 22 in the intermediate portion 8 of the manipulator arm 7, 8, 10 is designed in such a manner that the back portion 7 o the manipulator arm 7, 8, 10 can be turned in relation to the base 1 and the intermediate portion 8 can be turned in relation to the back portion 7 without the wires 28, 33 and 34 being acted upon so that the control rod 22 in the intermediate portion 8 is displaced longitudinally. According to the invention, this is achieved in that the first and third wire guide pulleys 29, 35 are mounted in the base 1 at the same or substantially the same distance from the mounting of the associated wire securing pulley 27 in the ~ase 1, and in that the back portion 7 is mounted in the base 1 so that the axis of rotation of the back portion 7 preferably lies near to the common centre line of the first and third wire guide pulleys, 29, 35, for example 1/36th of the diameter of the wire guide pulleys 29, 35 ~elow, and so that the axis of rotation of the back portion 7 lies equally far away : - 8 from the axes of rotation of the first and third wire guide pulleys 29, 35, while at the same time the diameter of the first and third wire guide pulleys 29, 35 is selected so that so much wire 28 or 33, 34 respectively is wound on the wire guide pulleys 29, 35 respectively where the centre spacing between the wire guide pulleys 29, 35 respectively and the second wire guide pulley 30 is shortened as a result of the movement of the back portion 7, that the wire tension is kept constant, and that so much wire 33, 34 or 28 respectively is unwound from the wire guide pulley 35 or 29 respectively where the centre spacing between the wire guide pulleys 29, 35 respectively and the second wire guide pulley 30 is lengthened as a result o movement of the back portion 7, that the wire tension is kept constant, which altogether means that the second wire guide pulley 30 is not rotated and that the rail 31 is not displaced longitudinally as a result of movements of the back portion 7 in relation to the base 1. The second wire guide : pulley 30 is further mounted in the ~ack portion 7 at a distance from the axis of rotation between the back portion 7 and the intPrmediate portion 8 which is equal to or substantially equal to the radius of the second wire guide pulley 30, and on a point on the straight line connecting said axis of rotation and the axis of ~ .rotation of the back portion 7 in the base 1, while at the same ; time the diameter of the second wire guide pulley 30 is selected so and the axis of rotation of the rocker arm 32 is placed so in relation to the axis of rotation between the back portion 7 and the intermediate portion 8, that, on a movement OI the intermediate portion 8 in relation to the back portion 7, so much wire 28, 33, _ g _ .~J
34 is wound and unwound respectivel~ in relation to the second wire guide pulley 30 that the ~ire tension is kept constant when the spacing between the axis of rotation of the second wire guide pulley 30 and the connection point between the rocker arm 32 and the rail 31 is altered as a result of movement of the intermediate portion 8 in relation to the back portion 7, which means that the rail 31 is not displaced longitudinally as a result of movements of the intermediate portion 8 in relation to the bac~ portion 7.
It has proved advisable for the diameter of the first and third wire guide pul~eys 2~, 35 to be 4/5ths of the diameter of the second wire guide pulley 30 and for the distance between the axis of rotation of the back portion 7 in the base 1 and the axis of rotation of the second wire guide pulley 30 to be at least five times the diameter of the second wire guide pulley 30. The wire attachment pulley 27 must be so large that the wires 28 r 33 and 34 respectively never lose contact ~ith the ~irst and third wire guide pulleys 29 and 35 respectively when the back portion 7 of the manipulator arm 7, 8, 10 is moved in relation to the base 1 within a desired range of movement.
2Q It wi11 now ba explained in more detail, with reference to Figures 3 and 4 of the drawings, how the front portion lQ of the manipulator arm 7, 8, 10 of the robot manipulator and its tool holder 11 are connected to and moved by the three longitudinally displaceable control rods 22, 23 and 24 mounted in the inter-mediate portion 8 of the manipulator arm 7, 8, 10.
The front portion 10 of the manipulator arm 7, 8, lQ
is adapted to be able to be turned in relation to the intermediate ~s~
portion 8 about the axes A-A and B-B in Figures 3 and 4 of the drawings by means of its universal-joint connection 9 to the intermediate portion 8 situated behind via a spindle 36 which is rotatably mounted in the intermediate portion 8 and the front portion of which is formed as a part of the universal joint 9.
The tool holder 11 is connected to the rotatable spindle 36 via the universal joint 3. Screwed to the free end of the spindle 36 is a screw 37~ the free end o~ which is received in a so-called ball nut 38 (not self-locking) secured to the free end of the longitudinally displaceable control rod 24. When the control rod 24 and hence the ball nut 38 is displaced longitudinally by -the associated hydraulic servo~cylinder in the base 1 being activated, the scre~ 37 will be turned on th~ same principle as the spindle in a pump inpeller, whereupon the tool holder 11 is turned correspondingly.
The front portion 10 of the manipulator arm 7, 8, 10 is formed with a transverse bearing ho~lsing 39 in which a journal 40 is rotatably mounted. The journal 40 cannot be displaced longitudinally in the bearing housing 39. The free ends of the longitudinally displaceable control rods 22 and 23 are pivotally mounted, each at its own end of the journal 40.
The two pivotable connections between the journal 40 and the guide rods 22 and 23 constitute two of three points in a three-point connection between the front portion 10 of.the manipulator arm 7, 8, 10 and the intermediate portion 8. The third point of the three-point connection consists of the universal joint 9.
~SB
When the front portion 10 of the manipulator arm 7, 8, 10 is to be turned in relation to the intermediate portion 8 of the manipulator arm 7, 8, 10, about the axis B-B, the control rods 22 and 23 are displaced equally. When the front portion 10 of the manipulator arm 7, 8, 10 is to be turned in relation to the intermediate portion 8 of the manipulator arm 7, 8, 10, situated ~ehind, about the axis A-A, the control rods 22 and 23 are displaced in relation to one another. It will easily be understood that the front portion 10 o the manipulator arm 7, 8 10 can be adjusted, up to a certain angle, in all possibl~ directions in relation to the intermediate portion 8 of the manipulator arm 7, 8, 10, b~ diferent displacement o the control rods 22 and 23.
In order to prevent the control rods 22 and 23 from twisting in relation to one another during the displacement of the control rods 22 and 23, there is disposed in the vicinity of ; the connections o the contxol rods 22 and 23 to the journal 40 a transverse member 41, one end of ~hich is pivotally connected to the control rod 22 and the other end of which is pivotally connected to the control rod 23. The transverse member 41 is 20 formed in the middle with a groove 42 in the longitudinal direction of the control rods 22, 23. Received for sliding in the groove 42 is the free end of a pin 43 which is rigidly connected to the intermediate portion 8 of the manipulator arm 7, 8l lO in such a manner that an extension of the centre line 44 of the pin 43 passes through the centre line 45 of the spindle 36.
It is clear from the above that in connection ~ith the invention all the hydraulic servo-cylinders of the ro~ot manipulator are placed in the base l of the robot manipulator and that linear movements from all the hydraulic servo-cylinders are converted into rotary movements by means of a crank device. In order that the servo-systems of the robot manipulator may be satisfactory, it is important that their position measuring systems should be closely connected to the hydraulic servo-cylinders, and that the servo~mechanisms should have substantially the same dissolution in the position measuring system over the whole range of movement of the tool holder 11. According to the invention, this is achieved in that all the servo-systems of the robot manipulator have an arrangement which is explained below with reference to Figures 5 and 6. In Figure 5, the reference numeral 46 designates any one of the hydraulic servo~cylinders of the robot manipulator. The servo-cylinder 46 is rigidly mounted in the base 1 of the robot manipulator, which base is not shown in Figure 5. The piston rod 47 of the servo-cylinder 46 is rigidly connected to the piston 48 o the servo-cylinder 46, which piston is formed with seali~g grooves 49 (pressure-distribution grooves).
At the other end, the piston rod 47 of the servo-cylinder 46 is rigidly connected to a member 50 adapted to slide with rolling friction 51 in fixed guides.52. Pivotally mounted on the member 5Q is one end of a link 53, the other end of which is pivotally mounted on the end of a crank arm 54 rigidly connected to a rotatable shaft 55 mounted in the base 1 of the robot manipulator.
The measuring system of the servo~cylinder 46, which is not shown in the drawing, is connected by means of a steel wire 56 to a projection 57 on the member 50.
.
r~
As a result of the fact that the length a of the crank arm 54 and the length b of the link 53 and the distance c between the axis of rotation of the shaft 55 and the centre line of the piston rod 47 are in the ratio of a to 1.80a to 1.33a in relation to one another and that the distance d between the pivotal axis of the link 53 on the member 50 when this is in the outer position, and the point of intersection between the cen-tre line of the piston rod 47 and a centre line perpendicular to this through the axis of rotation of the shaft 55 is 0.39a, and that the stroke length _ of the servo-cylinder 46 is~s6~, the effect is achieved that the linear piston movement of the servo-cylinder is converted into rotar~ movement of the shaEt 55 so that the relationship between the angular rotation of the shaft 55 and the corresponding changes in position of the piston 48 of the servo-cylinder 46 is substantia~ly constan~ over the whole working range of the servo-cylinder 46.
The substantially linear ~ransmission of movement described above from the servo-cyli~lder 46 to the rotatable shaft 55 is shown graphically in Figure 6 where the curve in the 2Q coordinate system shown indicates the angle V as a function of the distance of the member 50 from the normal down from the centre line of the shaft 55 when the stroke length _ of the servo-cylinder 46 is set at 200 millimetres. The two actual dimensions _ and _ are marked out in the ahscissae.
According to the invention, the friction between the pi~ton rod 47 and the piston-rod packing 59 in all the hydraulic servo-cylinders 46 of the robot manipulator is reduced to a , ~L2~7;}56 minimum by a special arrangement ~hereby the diameter of the piston rod 47 is reduced to below the bending limit for a piston rod freely mounted in conventional manner. The arranyement is shown in Figure 5 and will be explained in more detail below. It was explained above that the piston rod 47 is rigidly connected to the piston 48 of the servo-cylinder 46 and that, at the other end, the piston rod 47 is rigidly connected to a member 50 adapted to slide with rolling friction 51 in fixed guides 52. At the piston rod side, the servo-cylinder 46 is equipped with an end member 58 in which, in addition to a piston-rod packing 59t there is mounted a roller bush 60 through which the piston rod 47 is taken. The roller bush 60 is so long that the portion of the piston rod 47 which is inside the roller bush 60 at any time acts as if it were fixed. As a result of the fact that the piston rod 47 according to the invention is fixed at both ends, it has been possible to reduce the diameter of the piston rod very considerably in relation to the diameter o~ piston rod which, in view of the bend-ing circumstances, would have been necessary if the piston rod 47 had been freely mounted at both ends in the usual manner. In this manner, it has been possible for example, to reduce a piston rod diameter ~rom ~0 millimetres to 8 millimetres. This means that the circumference of the piston rod is reduced from 62.8 milli-metres to 25.1 millimetres. Since the friction between the piston rod and the packing is proportional to the pressure of the packing per unit area, the friction is reduced correspondingly.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device for robot manipulators of the kind which have a multiple articulated manipulator arm rotatably mounted in a swivelling base and wherein a front portion of the manipulator arm is rotatably connected, via a three-point connection, to a portion of the manipulator arm situated behind so that the front portion of the manipulator arm can be turned, up to a certain angle, in all possible directions in relation to the portion of the manipulator arm situated behind, by means of two longitudinally displaceable, substantially parallel control rods, one end of each of said rods being pivotally secured to the front portion of the manipulator arm and forming two of the points in said three-point connection, the third point consisting of a universal joint connection and wherein the manipulator arm with a tool holder is controlled by a system with hydraulic servo-cylinders, characterized in that all the servo-cylinders are placed in the base of the robot manipulator and that mechanical power transmission means are disposed between the tool holder or each of the parts of the manipulator arm respectively and the associated servo-cylinder, and that the front portion of the manipulator arm is formed with a bearing housing set transversely and in which a journal is mounted for rotation but not for displacement, and each of the parallel rods is respectively mounted on each end of the journal for pivoting, and a transverse member is pivotally connected to each of the parallel rods near the connection points of the rods to the journal, and the transverse member has a groove in the longitudinal direction of the rods, and a pin is rigidly connected to the intermediate portion of the manipulator arm and is received for sliding in the groove, wherein an extension of the center line of the pin passes through the center line of a spindle mounted in the intermediate portion, and said spindle is connected to the universal joint.
2. A device for robot manipulators of the kind which have a multiple articulated manipulator arm rotatably mounted in a swivelling base and wherein a front portion of the manipulator arm is rotatably connected, via a three-point connection, to a portion of the manipulator arm situated behind so that the front portion of the manipulator arm can be turned, up to a certain angle, in all possible directions in relation to the portion of the manipulator arm situated behind, by means of two longitudinally displaceable, substantially parallel rods, one end of each of said rods being pivotally secured to the front portion of the manipulator arm and form two of the points in said three-point connection, the third point consisting of a universal joint connection and wherein the manipulator arm with a tool holder is controlled by a system with hydraulic servo-cylinders, characterized in that all the servo-cylinders are placed in the base of the robot manipulator and that mechanical power transmission means are disposed between the tool holder or each of the parts of the manipulator arm respectively and the associated servo-cylinder, and that linear movements of the servo-cylinders are converted into a substantially proportional rotary movement over the whole working range of the servo-cylinders by the means of a crank arm, one end of said crank arm being rigidly connected to a rotatable shaft and the other end being pivotally connected to the one end of a link, the other end of the link being pivotally connected to a member which runs in a fixed guide and is connected to the piston rod of the servo-cylinder.
3. A device for robot manipulators as claimed in claim 1, characterized in that linear movements of the servo cylinders are converted into a substantially proportional rotary movement over the whole working range of the servo-cylinders by means of a crank arm, one end of said crank arm being rigidly connected to a rotatable shaft and the other end being pivotally connected to the one end of a link, the other end of the link being pivotally connected to a member which runs in a fixed guide and is connected to the piston rod of the servo-cylinder.
4. A device for robot manipulators as claimed in claim 3, characterized in that the length (a) of the crank arm and the length (b) of the link and the distance (c) between the axis of rotation of the shaft and the centre line of the piston rod are in the ratio of a to 1.80a to 1.33a to one another, and that the distance (d) between the pivotal axis of the link to the member when said member is in an outer position and the point of intersection between the centre line of the piston rod and a center line perpendicular thereto through the axis of rotation of the shaft is 0.39a, and that the stroke length (e) of each servo-cylinder is 1.56a, whereby the effect is achieved that the linear piston movement of the servo-cylinder is converted into rotary movement of the shaft so that the relationship between the angle of rotation of the shaft and corresponding changes in position of the piston of the servo-cylinder is substantially constant over the whole working range of the servo-cylinder.
5. A device for robot manipulators as claimed in claim 1, characterized in that the back end of each of the two longitudinally displaceable control rods in the intermediate portion of the manipulator arm and the back end of a longitudinally displaceable third control rod extending substantially parallel to said two control rods and adapted to rotate the tool holder about a longitudinal axis via a ball nut device and the universal joint, are each pivotally mounted on a rocker arm pivotally mounted on the intermediate portion, and each of the rocker arms is pivotally connected to and adapted to be turned by a longitudinally displaceable rail to the back and front ends of which respectively there are secured a first wire and a second and third wire respectively, first, second and third rotable wire guide pulleys being provided, said first, second and third wires being taken back or forwards respectively over said second rotatable wire guide pulley mounted on a back portion of the manipulator arm so far under the rotatable connection to the intermediate portion that it approximately corresponds to the radius of the second wire guide pulley, the first wire, steel band, chain or the like being taken further round the back of said first wire guide pulley rotatably mounted in the base and round the front of a wire attachment pulley rotatably mounted in the base, the first wire being secured to the attachment pulley, while at the same time the second and third wires, steel bands, chains or the like are taken round the front of said third wire guide pulley rotatably mounted in the base and round the back of the wire attachment pulley to which the second and third wires are secured, each of the three wire attachment pulleys of the robot manipulator being adapted to be able to be rotated by one of the servo-cylinders mounted in the base.
6. A robot manipulator as claimed in claim 5, characterized in that rotary movements are converted by means of the wires, steel bands, chains or the like from the wire attachment pulley mounted in the base via the first and third wire guide pulleys mounted in the base and the second wire guide pulley mounted at the upper end of the back portion of the manipulator arm into linear movements of the rail in such a manner that movements of the back portion in relation to the base do not influence the transmission, since the first and third wire guide pulleys are mounted in the base as the same or substantially the same distance from the mounting of the associated wire attachment pulley in the base, and the back portion is mounted in the base so that the axis of rotation of the back portion lies close to the common center line of the first and third wire guide pulleys, for example 1/36th of the diameter of the wire guide pulleys below, and so that the axis of rotation of the back portion lies equally far away from the axis of rotation of the first and third wire guide pulleys, while at the same time the diameter of the first and third wire guide pulleys is selected so that so much wire is wound on the first or third wire guide pulley where the centre distance between the first or third wire guide pulley and the second wire guide pulley is shortened as a result of movement of the back portion that the wire tension is kept constant, and that so much wire is unwound from the first or third wire guide pulley where the centre distance between the first or -third wire guide pulley and the second wire guide pulley is lengthened as a result of movement of the back portion that the wire tension is kept constant, such that the second wire guide pulley is not turned and that the rail is not displaced longitudinally as a result of movements of the back portion in relation to the base.
7. A device for robot manipulators as claimed in claim S, characterized in that the diameter of the first and third wire guide pulleys is 4/5ths of the diameter of the second wire pulley and that the distance between the axis of rotation of the back portion in the base and the axis of rotation of the second wire guide pulley is at least five times the diameter of the second wire guide pulley, while at the same time the wire attachment pulley is so large that the wires never lose contact with the first and third wire guide pulleys respectively when the back portion of the manipulator arm is moved in relation to the base within a desired range of movement.
8. A device for robot manipulators as claimed in claim 5, characterized in that rotary movements are converted by means of the wires from the wire attachment pulley mounted in the base via the first and third wire guide pulleys mounted in the base and the second wire guide pulley which is mounted at the upper end of the back portion of the manipulator arm into linear movements of the rail in such a manner that movements of the intermediate portion in relation to the back portion do not influence the transmission, since the second wire guide pulley is mounted in the back portion at a distance from the pivotal axis between the back portion and the intermediate portion equal to or sub-stantially equal to the radius of the second wire guide pulley, and preferably on a straight line between said pivotal axis and the axis of rotation of the back portion in the base, while at the same time the diameter of the second wire guide pulley is selected so, and the pivotal axis of the rocker arm is placed so in relation to the pivotal axis between the back portion and the intermediate portion that, on a movement of the intermediate portion in relation to the back portion, so much wire is wound and unwound respectively in relation to the second wire guide pulley that the wire tension is kept constant when the distance between the axis of rotation of the second wire guide pulley and the connecting point between the rocker arm and the rail is altered as a result of movement of the intermediate portion in relation to the back portion, such that the rail is not displaced longitudinally as a result of movements of the intermediate portion in relation to the back portion.
9. A device for robot manipulators as claimed in claim 1, characterized in that all the servo-cylinders of the robot manipulator have a piston rod the diameter of which is reduced to below the bending limit for a conventional freely mounted piston rod, since the piston rod is rigidly connected, at one end, to a piston of the servo-cylinder and is rigidly connected at the other end, to a member adapted to slide or roll in fixed guides, wherein the contact area and hence the friction between piston rod and piston rod packing is reduced to a minimum.
10. A robot manipulator as claimed in claim 9, characterized in that disposed between the fixed gripping of the piston rod at both ends is a roller bush through which the piston rod is taken, and that the roller bush is so long that the portion of the piston rod inside the roller bush at any time acts as if it were firmly gripped.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO813365A NO148986C (en) | 1981-10-05 | 1981-10-05 | ROBOT MANIPULATOR DEVICE |
| NO813365 | 1981-10-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1207356A true CA1207356A (en) | 1986-07-08 |
Family
ID=19886257
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000410423A Expired CA1207356A (en) | 1981-10-05 | 1982-08-30 | Device for robot manipulator |
Country Status (17)
| Country | Link |
|---|---|
| US (1) | US4531885A (en) |
| JP (1) | JPS5859778A (en) |
| AU (1) | AU564096B2 (en) |
| BR (1) | BR8207889A (en) |
| CA (1) | CA1207356A (en) |
| CH (1) | CH660997A5 (en) |
| DE (1) | DE3227508A1 (en) |
| DK (1) | DK153128C (en) |
| FI (1) | FI73616C (en) |
| FR (1) | FR2513926B1 (en) |
| GB (1) | GB2107279B (en) |
| IT (1) | IT1152692B (en) |
| MX (1) | MX156892A (en) |
| NO (1) | NO148986C (en) |
| SE (1) | SE8205499L (en) |
| SU (1) | SU1304741A3 (en) |
| WO (1) | WO1983001222A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104912309A (en) * | 2015-06-02 | 2015-09-16 | 山东漆品汇电子商务有限公司 | Overhead working spraying robot for steel structure building |
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| EP2637551B1 (en) | 2010-11-11 | 2019-10-02 | Medrobotics Corporation | Introduction devices for highly articulated robotic probes |
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| KR20140104502A (en) | 2011-12-21 | 2014-08-28 | 메드로보틱스 코포레이션 | Stabilizing apparatus for highly articulated probes with link arrangement, methods of formation thereof, and methods of use thereof |
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| CN104002304B (en) * | 2014-05-08 | 2015-11-25 | 昆明理工大学 | A kind of Novel pneumatic manipulator |
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| KR102214021B1 (en) * | 2016-12-06 | 2021-02-09 | 티엠티 태핑-매져링-테크놀로지 에스에이알엘 | Manipulator for pivoting rotation |
| CN109264635B (en) * | 2017-07-18 | 2023-09-29 | 山东宏大安装股份有限公司 | Large-space movable arm lifting mechanism for forklift robot |
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-
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-
1982
- 1982-07-23 DE DE19823227508 patent/DE3227508A1/en active Granted
- 1982-07-28 DK DK336382A patent/DK153128C/en not_active IP Right Cessation
- 1982-08-03 GB GB08222410A patent/GB2107279B/en not_active Expired
- 1982-08-04 JP JP57135293A patent/JPS5859778A/en active Granted
- 1982-08-30 CA CA000410423A patent/CA1207356A/en not_active Expired
- 1982-09-01 FR FR8214951A patent/FR2513926B1/en not_active Expired
- 1982-09-06 FI FI823074A patent/FI73616C/en not_active IP Right Cessation
- 1982-09-24 WO PCT/US1982/001353 patent/WO1983001222A1/en unknown
- 1982-09-24 BR BR8207889A patent/BR8207889A/en not_active IP Right Cessation
- 1982-09-24 AU AU90586/82A patent/AU564096B2/en not_active Ceased
- 1982-09-24 US US06/464,518 patent/US4531885A/en not_active Expired - Fee Related
- 1982-09-24 CH CH3145/83A patent/CH660997A5/en not_active IP Right Cessation
- 1982-09-27 SE SE8205499A patent/SE8205499L/en unknown
- 1982-10-05 MX MX194663A patent/MX156892A/en unknown
- 1982-10-05 IT IT23617/82A patent/IT1152692B/en active
-
1983
- 1983-06-03 SU SU833605467A patent/SU1304741A3/en active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104912309A (en) * | 2015-06-02 | 2015-09-16 | 山东漆品汇电子商务有限公司 | Overhead working spraying robot for steel structure building |
| CN104912309B (en) * | 2015-06-02 | 2017-08-11 | 山东漆品汇电子商务有限公司 | A kind of steel construction work high above the ground spray robot |
Also Published As
| Publication number | Publication date |
|---|---|
| US4531885A (en) | 1985-07-30 |
| NO148986B (en) | 1983-10-17 |
| GB2107279A (en) | 1983-04-27 |
| BR8207889A (en) | 1983-08-30 |
| CH660997A5 (en) | 1987-06-30 |
| AU564096B2 (en) | 1987-07-30 |
| SU1304741A3 (en) | 1987-04-15 |
| MX156892A (en) | 1988-10-10 |
| FR2513926B1 (en) | 1986-04-18 |
| JPS6146275B2 (en) | 1986-10-13 |
| DE3227508A1 (en) | 1983-04-28 |
| SE8205499D0 (en) | 1982-09-27 |
| DE3227508C2 (en) | 1987-12-17 |
| JPS5859778A (en) | 1983-04-08 |
| IT8223617A0 (en) | 1982-10-05 |
| FI73616B (en) | 1987-07-31 |
| WO1983001222A1 (en) | 1983-04-14 |
| IT1152692B (en) | 1987-01-07 |
| NO148986C (en) | 1984-01-25 |
| FI823074L (en) | 1983-04-06 |
| FR2513926A1 (en) | 1983-04-08 |
| DK153128B (en) | 1988-06-20 |
| DK153128C (en) | 1988-11-07 |
| FI823074A0 (en) | 1982-09-06 |
| NO813365L (en) | 1983-04-06 |
| AU9058682A (en) | 1983-04-27 |
| DK336382A (en) | 1983-04-06 |
| GB2107279B (en) | 1985-07-31 |
| SE8205499L (en) | 1983-04-06 |
| FI73616C (en) | 1987-11-09 |
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